The invention is directed to laser power output control and more particularly to a circuit to provide an effectively constant laser power output at the workpiece during movement of the laser along at least two different axes at various different speeds.
Pulsed gas lasers have found many and various uses in modern manufacturing processes. Such uses include but are not limited to the cutting of material such as metal, plastic and the like, the milling of metal, etc. These gas lasers are controlled by switching means driven by square wave pulses for repetitively energizing the pulsed laser discharge tube at a predetermined frequency by selectively providing a current path through the discharge tube. Selecting the switching frequency for laser systems used for cutting material or the like is determined by the speed of the movement along the material and the required power at the workpiece. This speed is substantially constant. When the cutting of material along two axes is required and the axes speeds are not substantially constant the selected frequency of the laser power control may be ideal for one fixed speed of movement and excessive or not sufficient for different speeds of movement. In this situation trial and error methods are used to establish a useable or compromised fixed frequency setting. In the cutting of materials along one axis for example, the trial and error method may be satisfactory; however, when a pulsed laser is used in the milling of material and is required to travel along two or more axes excessive or insufficient power at the workpiece cannot be tolerated for accurate milling. Ideally, the material being milled effectively receives constant power from the laser at changing speeds of movement of the various axes of the laser along the material. This insures the expected degree of milling of the material at all times. There has not been a satisfactory means of controlling the output power of a pulsed gas laser simultaneously moved along two or more axes at changing speeds until the emergency of the instant invention.